The present invention relates to an automatic resin dispensing apparatus and in particular to an improved device for precisely metering the proper ratio of resin and catalyst selected.
For proper application of polymeric resin materials such as urethane resin or polyester resin which require the addition of a catalyst or hardener to cure the resin, it is important that the appropriate ratio of catalyst to resin be maintained. Devices for automatically metering the relative amounts of catalyst and resin to be dispensed are known in the art. However, such devices tend to be rather large, complex and expensive. In addition, these prior art devices are frequently prone to failure, tend to be difficult and expensive to service, and often constitute a fire hazard.
It is the primary object of the present invention to provide an improved automatic resin dispensing device which is highly accurate over a wide range of catalyst to resin ratios, and yet is relatively simple in construction and therefore inexpensive to manufacture.
In addition, it is an object of the present invention to provide an improved automatic resin dispensing device that significantly reduces the fire hazard associated with such polymeric materials.
Furthermore, it is an object of the present invention to provide an improved automatic resin dispensing device that is more reliable than prior art designs, requires less maintenance, and is easy to service.
In general, the automatic resin dispensing device according to the present invention comprises a gear pump for pumping resin and a piston pump for pumping catalyst. Both pumps are coupled to and driven by a single air motor which is connected to the pumps through a dual output gear box. The input shaft of the gear pump is coupled directly to one output of the gear box while the other output of the gear box is coupled to a disk having a radially located pin that is connected to the shaft of the piston pump. By altering the radial location of the pin, the stroke of the piston pump is varied and the ratio of dispensed catalyst to resin adjusted accordingly.
In addition, to enhance the safety of the device, the resin pumping system including the supply lines running to and from the resin pump are separated from the catalyst pumping system including the supply lines running to and from the catalyst pump. Thus, the accidental mixture of the polymeric components if leaks develop, which may present a fire hazard, is substantially avoided.
Additional objects and advantages of the present invention will become apparent from a reading of the following detailed description of the preferred embodiment which makes reference to the drawings in which: